Method of and apparatus for treating guncotton and the like.



F. D. CRANE.

MUHUD OF AND APPARATUS FOR THEMING GUNCOTTON AND THE LIKE.

AI'I'LIL'AHON mu mu. [4. 19m.

1,295,089. I Patented Feb. 18, 1919.

wallsand moflntediuponthe upper-end at I northern or monrctam, Nnw

' Kim!) Eon'rmrnve GUNGO'ITON Tp aZl wk0m it mag concern: 1

Be it known that I, FREDERICK D. CRANE,

. a citizen of the United States, residing at Montcla ir, in the countyof Essex and State of New Jersey, have invented certain new and usefulImprovements in Methods of and;

Apparatus for Treating Guncotton and'the like, of which the following isa specification.

This invention relates to an improvement in the art of treating coherentmasses of material in a centrifugal wringer or drier. The

invention-"is especially adapted for use in then run into thecentrifuge-so as to thoroughly wash the-materiah Frequently during thesewringing operations', the gun cotton in the centrifuge spontaneouslyignites and produces a premature decom osition, the results of which areoften v waste '1 and disastrous. It is the object of the presentinvention to rovide means for preventing such decompositions, and alsofor facilitating the removal of theacids and other liquids from themass. To this end, the invention contemplates inclosing the centrifugein an air-tight casing and partially 'exhausing the air from suchcasing when a certain stage in the dryingoperation is reached. Theproduction of such a partial vacuum results in the rapid vaporization ofthe liquids contained in the gun cotton, and

this tends to cool and loosen up the mass, thus lessening the tendencyto spontaneous chemical action and allowing the liquids to drainou'tbetter."

In order that the invention may be clearly understood, reference is hadto the accompanying drawing, which diagrammatically illustrates oneembodiment of apparatus ar-' for carrying out my improved i In thedrawing, A represents an air-tight casing inclosing a centrifugal-drieror centrifuge B, preferably having foraminous- Specification of Letterslatent.

Patented Feb. is, -1 91;),

Application ianuary 14,1918; Serial No.2'11,8l9..

a shaft C, passing through a suitable'gasket in the bottom of the casingA. The shaft C- may be rotated by any suitable means, such, vforexample, as a power belt (not shown) working around the pulley 'D, se-

cured to the shaft. The casing A is providecl with a cover E, which .isso construct= ed as to be held to its seat by outside atmosphericpressure, but is unseated by i-1 ternal pressure.- A suitable pipe Fenters the cas ng above the centrifuge for the purposefof supplying washwater, or the like.

- From the bottom of the casing'A- extend waste pipes G and K, tosuitable receivers X and Y, respectively, the pipes being pro.-vi-dedwith-shut-ofl" valves Hand I, respectively'. Ifhe casin A ispreferably connected by means '0 the pipe'M with a rela-- tively largevacuum chamber Z. A suitable manually controlled'valve N is interposedin the pipe, Air is exhausted from the to Y chamber Z by means of a pumpP, of any suitable construction, connected to the chainbe r by-a pipe 0and driven froln'any suitablesouroe of power actingupon a pulley Q. Incarrying out niy invention, the pump P'is operated until the air hasbeen exhausted from the chamber Z, to any desired extent,- so thatv apartial vacuum is produced in this chamber, the valve N being closed, Amass of gun cotton to be treated is loaded into the centrifuge B and thecover E replaced. The centrifuge is then rotated at a "suitable speed soas to drive the contained liquids out of the mass. At a suitable stagein this wringing operation, the valve N is opened. This permits the airor other gases contained inthe casing .A to rush into the vacuum chamberZ, thus producing a sudden reduction of pressure 1n the casing A.

As a consequence, the volatile liquids contained. in the mass beingtreated rapidly";

vaporize, and. such vaporization produces a decided cooling of thematerial. It also loosens up the mass and facilitates the escape ofacids or other liquids. This loosen- 'ing up is also'due to theexpansion of the air or gas which is' trapped in the pores .of themateriah .The evaporation and eripansion above; mentioned also producesa slight drying action which facihtates the worl. of the centrifuges tothat extent. The cooling and -'loose ning up'of the mass tends toprevent.

's cutaneous action or combustion, as does a so the lessening of the airpressure surrounding themass,

It will be understood that the or the purpose of collecting the acidsand wash watersdischarged from the centrifuge, the valves H and L beingopened and closed at differ ent stages of IN whilemaintaining the pumpin oper- .atioii, a charge'or batch of material being treated maybesubjected to as many-successive reductions of pressure as may benecessary or desirable. v

I prefer .to employ a vacuum chamber Z, of relatively large size, asshown, in addition to the pump, rather than to rely upon a pump alone,since by means of the vacuum chamber, I can obtain a very suddenreduction of pressure in the casing A, and 'furthermore, the degree ofvacuum or the amount of reduction can be controlled as ratus .hereindescribed may be found useful for treating coherent masses of materialother than gun cotton, since, apart from the -med iurn s'urroundinexplosion-preventing function,- the invention has also the importantfunction of facilitato ing the action ofthe centrifuge-by loosening upand increasing the porosity of the mass. w WhatI claim is: a -L Theherein described method of treating a coherent mass in a centrifugaldrier which consists in producing a. sudden -defireduction in thepressure of the gaseous the mass, when the "mass reaches a certaindesired conditlon.

I the process. It will be'obviou's', also, that by opening andclosing'sthe valve signature.

which consists in drying the massto a certain extent and thereuponsubjecting it; to the action of a artial vacuum, whereby thecontainedllq'ui is suddenly vaporized, thus looseningmp the mass. 3.That improvement in the art of manufacturing gun cotton or the likewhich con sists in sub ecting it while acid wet to the action ofracentrifugal drier in a partial vacuum.- 4. In the art of manufacturinggun cotton and the 'like, in which the acid wet'mass is treatedina'centrif ug'al drier; that improvement whichconsists in suddenlysubjecting such mass to the action of a partialvacuum, whereby theiiiass -is cooled and rendered porous by the resulting rapidvaporization fofthecontained liquid, desiredlby the operator, by meansof the valve N, independent of the speed or capacitylofthe' pump. It isobvious that the method and'apparapid vapor zation of the-containedliquid serves to cool and loosen up *the mass. 6. In apparatus of theclass described, the

combination with a centrifugal drier, of an air-tightcasing inclosingthe same, a relatively large vacuum chamber, a valve controlled conduitconnecting said casin and chamber, and means for exhausting t e air fromsaid vacuum chamber.

In testimonywhereof I have afiix'ed my FREDERICK D. CRANE.

